The present invention relates to polypeptides having D-amino acids which inhibit the binding of leukocyte function-associated antigen (LFA-1) and intracellular adhesion molecule (ICAM-1). These D-form polypeptides can be used to treat disorders such as rejection of transplanted organs, allergies, and autoimmune diseases.
Many autoimmune diseases occur when T-cells of an organism recognize and react to xe2x80x9cselfxe2x80x9d proteins. This recognition occurs when specific proteins on the surface of the T-cells bind to the corresponding self proteins. This type of reaction results in such autoimmune diseases as rheumatoid arthritis, insulin-dependent diabetes mellitus, multiple sclerosis, and allograft rejection.
Initiation of an immune response to an antigen involves interaction of a small subset of T-cells with the antigen, followed by activation and proliferation of those T-cell clones. Complete T-cell activation requires two signals: (1) a first signal resulting from the interaction of the T-cell receptor with an appropriate MHC-antigen complex, and (2) a second signal provided by adhesion molecules. The second signal may be provided by binding of the adhesion receptor, LFA-1 (CD11a and CD18), to one of its counter-receptors such as ICAM-1 (CD54) (Staunton et al., 1990, Cell 61:243-254). If the second signal is blocked, the antigen-specific T-cells are induced to die by apoptosis or to enter a state of cellular anergy. Blockage of this interaction by monoclonal antibodies to LFA-1 and ICAM-1 results in increased survival time for mice receiving a heart allograft (Isobe et al., 1992, Science 255: I 125-1 127).
The present invention is based on the seminal finding that D-amino acid polypeptides having sequence homology with cell adhesion molecules, such as ICAM-1 or LFA-1 can inhibit interaction between a particular adhesion receptor and its counter receptor or ligand.
For example, D-amino acid polypeptides with homology to either LFA-1 or ICAM-1, can bind to either ICAM-1 or LFA-1, respectively, and these D-form polypeptides used to inhibit undesirable interaction between ICAM-1 and LFA-1.
In a first embodiment, the invention provides a polypeptide having a sequence comprising one or more D-amino acids, wherein the polypeptide is derived from an LFA-1 binding site. In a preferred embodiment the polypeptide sequence has a sequence as set forth in SEQ ID NO:6.
In another embodiment, the invention provides a polypeptide having at least one D-amino acid, wherein the polypeptide has a sequence as set forth in SEQ ID NO:6. In another aspect of this embodiment, all of the amino acids of the polypeptide are D-amino acids.
In another embodiment, a method of inhibiting the interaction of ICAM-1 and LFA-1 by contacting a sample containing ICAM-1 and LFA-1 with a polypeptide having at least one D-amino acid, and having a sequence as set forth in SEQ ID NO:6, is provided. In another aspect of this embodiment, all of the amino acids of the polypeptide are D-amino acids.
In yet another embodiment, the invention provides a method for inhibiting an integrin-associated disease by contacting a subject with an inhibiting-effective amount of a polypeptide having a sequence comprising one or more D-amino acids, wherein the polypeptide has a sequence as set forth in SEQ ID NO:6. In one aspect of this embodiment, the integrin-associated disease is selected from the group consisting an allergy, an autoimmune disease, transplant rejection, and the autoimmune disease is selected from the group consisting of rheumatoid arthritis, insulin-dependent diabetes and multiple sclerosis. The subject may be any mammal, but is preferably a human. The contacting may be done in vivo or ex vivo.
In yet a further embodiment, a therapeutic composition comprising, a polypeptide derived from an LFA-1 binding site, wherein the polypeptide has a sequence comprising one or more D-amino acids and has a sequence as set forth in SEQ ID NO:6, is provided.
The details of one or more embodiments of the invention are set forth in the accompanying figures and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.